Author: roofvent

Ventilation and insulation are important factors you should always consider for your roof. Without these, your roof will trap a lot of heat during the day. By accumulating a lot of heat, your home will become hotter than it’s supposed to be, especially during the summer. Through radiation, the excess heat warms your home, leading to a heat gain of up to 35%. This is almost the same as the amount of heat gain your windows allow in. Fortunately for the windows, you can simply install blinds. However, you cannot install blinds over the roof.

Your home becomes hot and stuffy as the heat keeps seeping in through the ceiling. The next thing most people do is to install air conditioning. This is a knee-jerk reaction, which will barely solve your problem. The unventilated roof will keep transferring heat while you keep using air conditioning for longer. In the long run, your utility bills will surprise you.

Over the years, there have been improvements in the methods that you can use for roof ventilation. Most people are used to the roof whirlybird which has been around since 1910. By design, the principles behind the whirlybird haven’t changed. The turbine still depends on the wind to spin and cool your roof. Another factor is air expansion in the roof cavity, which happens as the temperatures rise.

How Does the Whirlybird Work?

 There are two types of whirlybirds:

• The wind-driven whirlybird
• The mechanical, active-powered whirlybird

The wind-driven model is the most common, and popular. It depends on the wind to turn the turbines, thereby rotating the vents. The resulting motion creates a vacuum which sucks air from the roof cavity. As effective as this is, a single whirlybird is unfortunately not enough to cool a modern roof. In fact, most homeowners need up to six units for optimal results.

One benefit of the whirlybird is that it can also help you improve the air circulation in your home, while at the same time reducing heat build-up. This design can also withstand rain, though this doesn’t mean it’s impenetrable.

Is It Effective?

In terms of efficiency, each whirlybird is different. Your results will depend on the model and the manufacturer that you purchase from. However, on average your whirlybird should ventilate between 100 and 150 m³/h for 12 km/h winds. Take note that this performance might not be the same always. There are also other factors that will affect the performance, that have nothing to do with the whirlybird. For example, the accessibility of wind, and how warm the air in the roof cavity is (to allow for expansion). Other than that, the throat size of your whirlybird, wear, and tear will have an impact on the effectiveness of this device.

For efficient ventilation, you need around 700 m³/h of air flow just to keep your roof cavity as close to the outdoor ambient temperatures as possible. This means that you will have to buy more than one whirlybird.

Is the Cost Worth It?

 Contrary to what most people might think, a normal whirlybird is quite affordable. Visit any of the local hardware stores and you will find them for around $60 AUD. Apart from that, you can install the whirlybird on your own. While affordability is something you might be excited about, this can be a challenge today, because there are many cheap models on the market, which might not be very efficient.

Whirlybird Downsides

 The following are some of the challenges that you might experience when you buy wind-powered whirlybirds for roof ventilation:

• Dependant on Airflow

To turn the turbines, the whirlybird depends on the wind. Therefore, to put it simply, when there’s no wind, the whirlybird won’t be effective. On a windy day, you can enjoy the best ventilation for your roof. However, on those days when there’s no wind, especially the humid summer days, the sun will have as much fun as it pleases, roasting your roof.

If you live in valley areas, strong winds are the order of the day. Therefore, your whirlybird will always perform optimally. If this is not the case, you might need to consider other alternatives. One such option is a mechanical whirlybird. These are very good, though their prices and cost of operation have proven quite inhibitive in the past.

• Makes a Lot of Noise

 Cheap is always expensive. The same applies to whirlybirds. If you get the cheap ones, rest assured they will make a lot of noise, and might also not be as efficient as you would expect. While in operation, the parts of the whirlybird rub against each other, making low grinding or squeaking noises. As the strength of the wind increases, so does the noise. Other than that, the whirlybird has movable parts, which means you should constantly lubricate them. Fail to do this and the bearings will loosen. Should they get damaged out of neglect, your whirlybird will become incessantly noisier.

• Flawed Design

 We have already mentioned before that most whirlybirds are quite affordable. Compared with more expensive ventilators in the market, they are inefficient in terms of moving air through your roof cavity. A single whirlybird will never be sufficient for your home. You need more in order to reduce the temperature in your home. In fact, a standard average home requires 15-20 whirlybirds. If you manage to install all these whirlybirds, it will be expensive. Other than that, it will also make the installation costly, cumbersome, and will interfere with the overall look of your home.

• May Malfunction

Whirlybirds are built to work in the rain. However, they feature an open design, which may trap foreign objects, dust, and leaves. The more debris is trapped in the whirlybird, the more likely that it will not perform optimally. There are cheaper models in the market that will not last long before the effect of severe weather damages them. You can avoid this with proper cleaning and maintenance. However, imagine doing that for 15-20 whirlybirds, just to make sure your home is cool. Most people cannot do this so it becomes an inconvenience.

Ventilation for Commercial Properties

 An average whirlybird requires 8 km/h wind power for optimal results. Industrial models, however, can operate between 2500 and 5000 m³/h, especially where there are very strong winds.

Even though most people are only used to the whirlybirds for homes, there are also commercial ventilation products available which are designed to help cool down the heat that’s produced in such properties. Other than that, commercial ventilation whirlybirds are designed with exhaust fans that will help propel fumes away from your industrial premise.

Commercial solar ventilators are available in two sizes:

• SW-RAF7000, capable of moving 7,000 m³/h
• SW-RAF10000, capable of moving a whopping 10,000 m³/h!

Dealing with Whirlybird Leaks

 A whirlybird is simply an exhaust vent. These vents are built with fins. The fins open as they turn in the wind. This creates a spinning action that draws humid air in your attic outside. Usually, you will not need maintenance for your whirlybird. However, this is not to say that you might not encounter problems from time to time. One of the challenges that you might experience is a leaking whirlybird. While replacing the vent might be a solution, it’s not always the case.

• Obstructions and Rust

 The way the whirlybird is designed, even the slightest breeze can turn the turbines. When the vent is spinning, the air that’s blown from it should be sufficient to blow rain from the openings of the whirlybird between the whirlybird fins.

In case you have a rusty vent, it might not be able to turn as it’s supposed to, and will be sticky. As a result, rainwater will leak into the whirlybird. You should inspect the whirlybird because there might be something inside or close to it that might be making it impossible to turn as it’s supposed to. Remove any obstructions close or inside the whirlybird, and replace the rusty vents.

• Loose Connections

 When the wind is too strong, the vents might loosen from the standpipe. This is one of the reasons why water can seep into the whirlybird. You will notice that some turbine vents have a friction fitted on top. In case the flange connecting the roof sheath and the pipe is not anchored properly, this will also create an opening for water to seep into the whirlybird.

These are some of the things you need to inspect. Ensure the spinning section has been anchored securely with metal screws. In case the flashing is loose, use roofing nails of rust-resistant screws to fasten it in place. Use roofing cement or silicone caulk to seal around the fastener heads that are exposed.

• Fasteners and Unsealed Joints

 Upon installation, several parts of the turbine vents are sealed to prevent water from seeping inside. The parts that are sealed with silicone caulk and roofing cement include the nail heads, the base of the vent, the vertical seams and the bed that connects the upper and lower parts of the whirlybird. The seals will, however, suffer wear and tear over time, and you will need to reapply them to protect the whirlybird.

• Improper Flashing

 As you inspect your turbine vents, you might realize that it’s in proper condition, all the fins are in place and it’s running just fine. However, it might still be leaking at the base of the vent. Most of the vents are built with a unique base flashing. The flashing is made from sheet metal. The sheet metal slips above the vent and overlaps the shingles.

In case the flashing is damaged or is bent, the force of the wind can make rain penetrate the whirlybird from underneath. You should, therefore, reattach the parts of the flashing that might be raised, seal the fasteners and edges with roofing cement and caulk. If the flashing is corroded, it might have holes that are holding water. If this is the case, you will have to replace the vent altogether.

DIY Installation

 Most of the mounted whirlybird ventilators are very easy to install on your own. You should find instructions included when you buy them, which are very simple and easy to follow.

Here are some of the steps that you should follow:

• First, determine the part of the house where the vents will be installed. This should be the side furthest from the entrance.
• Estimate the number of ventilators that will be enough for your roof. The ideal setting should be one vent for every 50 m² of your ceiling. This might also depend on the type of whirlybird that you buy.
• Make sure you don’t cut through rafters when installing the ventilators. This is because, during installation, most of the roofers often drill nails from the side to indicate the centre line.
• Clearly indicate the parts of the roof that you will saw through.
• In case your house has a metal roof, you must get the right saw blade to use with your reciprocating saw. If yours is a tiled roof, you must first remove the tiles that are in the part you want to cut through.
• Always cut according to the specifications for your reciprocating saw.
• In the course of installation, make sure you use caulk so that rain doesn’t affect the installation.

While installing the ventilation, you have to exercise caution so that you don’t interfere with the roof and create leaks. This is one process that most people fail at.

These are basic steps and they should guide you. However, since ventilation products might be different, the procedure might also differ from one product to another. Where possible, hire an expert to handle the installation on your behalf.

Choosing a Roof Mounted Ventilator

Long before whirlybirds were used in homes, they were common in commercial buildings and industrial settings. Therefore, the style didn’t matter much. However, at the moment there are different types of vents. When you are searching for the best, make sure you get the ones that are rust and corrosion resistant. Make sure you check the quality of the ventilator before you pay for it. Some of the best products come with a warranty of more than 15 years, and they might be more expensive than most of the average ventilators.

Calculating the Amount of Ventilation You Need

The tips below apply for homes that have ventilated antics. There are some homes where the roofing is designed with ventilation space in the roof instead of the attic, especially in flat roof houses. In such instances, you will have to take additional measures to calculate the ventilation.

For ideal ventilation between the attic and the roof, you must establish a good balance. The space set aside for air intake must be the same as the space set aside for exhaust, and this will depend on the slope of the roof, and the size of your attic.

To determine the requirements for ventilation, you must first take measurements for the length and width of the attic floor. Compare this with the net free area (NFA). The NFA is used to rate the vents, which is simply the space set aside for free circulation of air. This makes it easier for you to determine the number of vents you need for the attic.

In case your attic floor is designed with a vapor barrier you will need a square foot of NFA for every 300 square feet of the attic floor. In case you don’t have a vapor barrier, increase this to a square foot of NFA for each foot of the attic floor.

These guidelines are basic, and in most cases, they will cut across the board. However, it’s always wise to consult your local building code.

In case your roof has a steeper slope than most homes, your NFA calculations won’t be the same. The average slope should be 6:12. If yours is bigger than this, you will have to make room for more ventilation. If your slope is in the range of 7-10:12, allow for 20% more space. If your slope is 11:12 or higher, allow for 30%.

Once this is done, you can then choose the type of vents that will suit your home. Remember that it’s safer to have more intake ventilation than a deficiency. Most people get their calculations wrong and they underquote the amount of intake necessary. Therefore, don’t worry yourself about having too much ventilation.

When ventilating the attic, one of the best things you can do is to make use of the warm, moist air and its ability to rise, particularly when cold air under it keeps pushing it up. Owing to normal activities in the home like showering, cooking or human physiology, there’s never a shortage of warm moist air in the home.

You should, therefore, find a way to take advantage of this effect. Your roofer will install intake vents as close to the eaves as possible, and install exhaust vents on the higher side closer to the peak. This helps to push out hot air more efficiently.

Don’t Block the Vents

You should never block the vents. You wouldn’t want to stuff insulation in the vents either. During the winter, ventilating the attic spaces is necessary as compared to the same during the summer. Water vapor from your home will rise into the attic each day.

The Problem with Condensation

If the vapor is not removed from the house as fast as possible, there’s a risk that it will condense on the frame of the roof, or beneath the roof sheath. When this gets intense, water might start dripping from under the roof, and as the temperature falls, it might frost within the attic. These are some of the prime conditions for mold growth or wood rot.

Thousands of CFM per Hour

Turbines can help you propel as much humid air out of the house as possible, depending on the size of the vents, and the speed of wind outside. A turbine vent with a diameter of 12 inches and a steady speed of 5 mph can get rid of more than 340 cubic feet of air per minute (CFM) from the attic.

A turbine bent of 14 inches and a steady speed of 15 mph can get rid of more than 1300 CFM of air. In case the winds are still, the vents will still help with proper inflow and outflow of air through the attic, though not as much as when the winds are strong.

Don’t Steal Heat

There’s always the myth that during the cold months, vents will remove warm air from the attic. In case it’s cold outside while the air in the attic is warmer, you might experience inefficient insulation especially when you’re in the attic on a sunny day.

The best thing to do is to make sure you monitor the attic temperature soon after the sun has gone down at night. With proper insulation, the air temperature in the attic should almost be the same as the temperature outside the house.

AC Leaks

There’s also the possibility that turbine vents can draw conditioned air from within your house. According to modern building guides, you should have soffit ventilation vents which will help with air intake.

When the vents are drawing air from the attic, the same amount of air should be flowing into the attic where the roof crosses over the exterior walls of your home. This applies across all types of vents, whether you have an electrically powered fan, ridge vent or turbine vent.

In case the soffit air getting in is not sufficient, you might have a partial vacuum in the attic. This pressure will force the vacuum to draw air from within your home, and you wouldn’t want that to happen.

Aluminum and Rust

Should you decide to add more vents to the roof, consider getting aluminum vents. This is because aluminum doesn’t rust. Other than that, make sure you consider the roof pitch that will be ideal for the turbines you buy. Your turbines should be adjustable in such a way that the spinning section is level even if you have a slanted roof. Remember that all turbines will not always fit your roof pitch. Look at the box label carefully to identify the maximum roof pitch.

Lubricate Bearings

Always make sure that all the ball bearings have been sealed and lubricated. You wouldn’t want to have a squeaky turbine making noise, especially on a windy night.

When summer temperatures record triple digits, the last place you want to be is in your attic. Having a closed-off attic will be not good for your cooling and heating system, right? Would it be great if you can vent that hot air out and remove it entirely from your house?

This is where the solar-powered ventilators can help you. These devices are designed to keep your attic cooler and help lower your overall energy cost. However, this has remained controversial among the professionals in the building industry because there’s no clear evidence on how effective these devices are or whether they are safe to use. In this article, you’ll find out the ins and outs of using these machines and understand how they are different from your home ventilation system.

A Brief History on Powered Ventilators

Before we go into the specific details of the solar-powered roof vents, let us first understand what attic ventilation is. This topic may not be something that you get to talk about often, but this is important for your home health.

Powered ventilator experts have said that these devices can extend the life of your roofing and helps to prevent the growth of mildew in your attic. Furthermore, the device also helps to make your home less susceptible to molds while minimizing the buildup of ice during winter. The main purpose of the powered ventilation system is to minimize heat gain across the roof and ceiling of your home and prevent the moisture from condensing in these areas. This is extremely important because according to studies, most of the houses in the US experiences excessive humidity.

Keeping your attics dry and well ventilated can help to stabilize the temperature in your roof and reduces the chances of mold, deterioration, and rot.

However, not everyone would agree with these claims. There are some roofing professionals who would say that instead of helping to lower the temperature in your attic, the powered ventilators would instead bulk-up your energy expenses since it sucks the cool air out of your home and this will funnel electricity off the grid to get things done.

On the other hand, every time you increase the number of openings of your roof to install the ventilator, you’ll increase your risk to leaks, and this could counteract with the ventilator’s moisture-reducing abilities.

Building oversight and research groups generally believe that more studies are needed to dismiss or backup the humidity and temperature claims of the device. This is because some of the initial studies in this area have shown some flaws, such as leaky ductwork, as well as limits because of the weather conditions and time constraints. A much better approach is to take into consideration the ventilation system of your home in the same way that you would on the cooling and heating system. It should be equal to the size and demand of your home.

What’s a Solar-Powered Ventilator Exactly?

Among the disagreements about the attic fans and the ventilation system has something to do with the confusion on its terms. It’s important to define the exact difference between the powered attic ventilators and the whole house attic fans.

Attic fans are designed to keep your homes cool at night. It usually works along with large passive vents at the rooftops and draws warmer air indoor, towards the attic where it gets exhausted into the roof vents. The windows in the downstairs are usually left open to allow for the cold nighttime air to get in, which helps to lower energy expenses.

On the other hand, powered ventilators are not a type of home cooling system, yet they tend to get confused with the whole house attic fans since they are technically fans and have similar goals and that is to reduce the overall cooling demand in a house. As a result, energy consumption will be lowered, and the attic will be ventilated. However, instead of cooling the entire house, the powered ventilators will work by exhausting hot and humid air from the attic. This method allows the cooled air outdoor to fill your home via the soffit vents. The system is usually attached to a thermometer responsible for turning the fan off and on, whenever the heat in the attic would increase above a specific temperature.

It sounds awesome, right? However, there are certain factors at home that could throw the equation off. For instance, if your attic is not sealed properly, the ventilator could pull the air-conditioned air into the gaps and will bring it outdoors. This will increase the heat in your home instead of reducing the need to use the air conditioning system. Furthermore, the ventilator can also depressurize your attic interior, and according to some findings, this could increase the carbon monoxide in your home, as it will make the water heaters to backdraft.

The solar-powered ventilators have been made to counter the claims that electric-powered roof vents are saving energy. Because the fans were powered naturally, they would not be sucking energy off the grid, which negates any energy savings resulting from better ventilation. A team of researchers from Florida Solar Energy has tested the solar-powered ventilators, and they have discovered that they did have a positive effect on home energy and reduced the homeowner’s dependence on air conditioning system.

However, some energy experts would still maintain that the savings represented by the solar-powered ventilators, which is said to be $37 per year, would not be enough to recoup the cost of getting the equipment installed, which averages at $850, excluding the labor cost.

Are Solar Attic Fans or Roof Vents Really Worth It?

Just like with the other green home renovations, the answer would be, “it depends.” They are certainly not recommended if you’ve got combustion gas appliances, such as the gas-powered water heaters because there is a potential for backdrafts. However, if your goal is to make your home energy efficient, regardless of the cost you’re going to incur, then this equipment can be a positive addition. This is especially true if you wanted your attic to be cooler. For instance, you are using it to store valuables that you don’t want to expose to humidity and heat.

Also, if your house tends to suffer from excessive heat from your attic, installing the solar-powered ventilator is a potential solution to lowering the temperature inside your home and keeps your roof protected.

Other Ways to Cool Your Attic and Optimize Your HVAC System

If the attic in your home is feeling stuffy and humid, and gets excessively hot, using the powered ventilator is not the only option. As a matter of fact, coming up with a well-designed ventilation system can do the job just as well. To allow for an adequate amount of air to flow into your attic, half of the vents must be placed high into the rooftop. If possible, at the topmost peak, while the other half should be placed at the roof’s lower portion. This can help to create a natural circulation of air, allowing for the hottest air to rise into the much higher vents.

Proper sealing and insulation can also help. Filling the cracks in the ceiling can help prevent the cool air from seeping towards the unconditioned attics. Once you have sealed up these areas, consider adding insulating to the flooring of your attic.

If the HVAC system of your home runs all throughout the attic, you’ll be able to experience better performance once you move the ductwork towards your home interior. That way, you no longer need to worry about how hot the attic can become. Ensure that the seals in between the ducts are closed properly to keep the cooling and heating system from leaking.

These changes can help to improve your HVAC’s efficiency all throughout the entire year and not just during the hottest months.

However, if you’re interested in the use of solar ventilators because you find it appealing to moderate your roof temperature, then there are some “low-tech” solutions that you can apply to keep the temperatures down. First, consider the use of lighter-colored roofing. Darker roofs tend to absorb more heat. Lastly, consider planting some trees in your surroundings. This will provide you with long-lasting benefits, including shadier roof, and above all, it can help to improve your home’s façade as well!

Choosing the Right Solar Roof Ventilator

Although the manufacturing cost of solar panels is decreasing, a high-quality solar panel and motor are often the most expensive parts of the solar roof ventilators. You can expect to pay around $500 to $900 for a product that’s guaranteed to last. Compared to the recommended 2 to 4 whirly birds, which costs $200 each for a standard size home, a Single Solar Star is definitely worthwhile.

• Performance

There have been lots of performance claims on the market. However, the solar-powered roof ventilation is going to make a huge difference, unlike the wind vents. So, what are the important factors that you need to take into consideration when buying the roof ventilation?

The best way to determine is to understand the solar panel’s wattage as well as the diameter of the extraction fan. Although there are other variables, this should be the easiest comparison.

• Warranty

Although it is typical to offer a warranty of 10 to 15 years for the solar panel, make sure you review the fine print. Most warranty will include the components, usually offering 1 to 3 years of warranty for the motor.

• Installation

With the various imports being directly shipped from outside the country, customers must be careful with choosing the right product to use. A single and one-size flashing can lead to similar issues of leaking like the traditional and low-quality skylights. Consumers must choose the flashings that are custom-made to fit with the contours of their roofing.

• Market Prices

Wind vents cost between $80 and $350 per unit.

Average air volume is tested at about 80 to 100m3 per hour, and this is relatively inefficient. Usually, these products have the same performance as that of a static cap. They are in high demand in the Australian market since they are cheaper to include in roofing and insulation packages.

The main factor in the pricing of the wind vents is quality.

Here’s what you should look for:

• Does it come with a fan blade – the blade is extremely helpful regarding improving air extraction.
• What about the diameter of the product – for domestic homes, the diameter usually ranges from 250 to 350mm.
• Warranty – the bearings is one of the most important concerns on wind vents. You’ll see several low quality wind vents that have bearings that produce annoying sounds.

Budget Solar Roof Vents Cost $100 to $250 per Unit

When looking for a solar powered product to buy, you should be ready to spend a bit more for a high-quality system. Budget roof vents that are solar-powered are usually cheap because they are made from poor quality solar panels and motors. This could lead to poor performance of the product, providing little to no benefit unlike with a standard wind vent that usually comes with a warranty. If this is your budget, you might as well stick to a high-quality whirlybird.

Quality Solar Roof Vents Cost $500 to $900

We’ve already talked about how to choose the proper product type. But what about the most common questions and requests?

How Much Can Roof Ventilation Lower My Home’s Temperature?

This question is almost impossible to answer since there are lots of factors to consider such as the roof material, insulation, and the tiles. The best way to find out how the ventilation is going to work is to place your head into your roof cavity and try to feel the temperature. The temperature on your roof cavity could reach 60 plus degree easily, so replace this air with a much cooler air from the outside.

How Many Eave Vents to Install?

There are various recommendations when it comes to this. However certain factors like sarking on a tiled have the most major impact. One way to identify this is by opening the manhole at your ceiling. If you’re still feeling a substantial amount of air getting drawn into the manhole even after the ventilation has been installed, then you probably need more eave vents.

Do They Operate at Night?

Most of these devices work in the same way as the whirlybird, however, instead of working along with the wind, they operate using the sun.  The whirlybird will not work during a hot and still summer day, while the solar roof ventilator will not motorize at night. Wind vent has the same performance as that of the static cap. The solar roof ventilator would still allow for natural air at night.

• Batteries can’t work well with extreme temperatures – There have been several recalls for battery-operated roof products due to fire hazards.
• Batteries usually come with a one-year warranty, but depending on the quality, the batteries must be checked from time to time and replaced at least after a year or two.
• Battery backup – This needs to be requested, however, you must be aware of the pitfalls and consider the extra costs.

Rainy Days

The Solar Star can still operate enough to bring in moisture from your roof cavity. However there’s little need for the device to run in full capacity. Roof ventilators often draw air from the outside, and the conditions of the outside air will determine its impact on your home.

What You Should Know About Whirlybirds

Without proper ventilation or insulation, a standard roof space traps and accumulates heat, as the sun will get into your roof. The heat radiates towards your ceiling to warm your home. This accounts for 25 to 35 percent of heat gain during summer. It’s obviously possible to install blinds to block the heat on your windows. However, you cannot place blinds over your roofing.

Once the heat in the roof starts to seep into your ceiling, your home will become hot and stuffy. Normally, homeowners will resort to air conditioning, although unventilated roof spaces will continuously transfer heat. If you don’t have the means to keep your home cool longer, your electric bills will surely skyrocket.

Over the past years, the process to ventilate your roof has drastically changed. The product that most homeowners are familiar with is the roof whirlybird. Samuel Ewart made one of the first few designs of the whirlybird in 1910. The design principle has not changed much in decades since it still relies on the wind in producing turbine spin. They could also rely on the expansion of the air in your roof cavity resulting from the rising temperatures.

How Do Whirlybirds Work?

The whirlybirds are available in two types – conventional wind-driven and the mechanical, active-powered. The more popular of the two is the conventional whirlybird that works according to the wind. Once the wind hits its turbine fins, it will trigger the vents to rotate. The motion will create a vacuum that would suck the air out of the roof. However, a single whirlybird may not be enough for a modern home and would require up to 6 units before you could feel the effect.

It’s worth it to note that these devices can help to reduce the buildup of heat and humidity while improving the circulation of air inside your home. The design can also help to resist rain, although this is not impervious.

Is a Whirlybird Effective?

Depending on the manufacturer of the whirlybird, as well as the model that you have chosen, each average unit is capable of ventilating 100 to 150 m³/h in a 12-km/h winds. However, the performance will naturally vary from one design to another. These factors will range from how warm the air in your roof space, wind accessibility, throat size of the whirlybird, and the wear and tear of the unit itself.

For you to feel the full effects of ventilation in your home, you need up to 700 m³/h of airflow to keep the space in your roof stay at near ambient to the temperature outside your home. But this also means that you will need more than one unit of whirlybird to be able to do the job well.

Using Ventilation for Commercial Purposes

Whirlybirds that are intended for industrial use need extremely strong winds to be able to operate somewhere between 2,500 and 5,000 m³/h for every hour, while the average unit needs only around 8 km/h to provide satisfactory performance.

Although the solar roof ventilation systems are mainly intended for home use, we also offer units for commercial use. They were properly designed to ventilate extreme heat, which large-scale properties tend to produce. Also, the commercial exhaust fans are great at adequately ventilating fumes on commercial properties.

Dedicated Roof Ventilation

Conventional whirlybird is old school. Its aging design has now been replaced by a far more effective and highly dedicated ventilator system. While they are still being produced nowadays and can be seen at various homes, more and more homeowners are turning into solar roof ventilation to meet their home extraction and cooling needs. Documented studies have also shown that most of the modern roof ventilator system casts a shadow over the cheaper version of the whirlybirds.

The Solar Whiz ventilator is ideal for DIYers. It’s also free to operate during the day, although it also comes with nighttime options. It’s also available in a wide variety of sizes, depending on your needs. They could easily out-perform 15 to 20 units of whirlybirds.

The old concept of using wind in ventilating a roof space is now declining. Besides, why do you need to rely on the wind in ventilating your home if the issue is the sun? So use the sun to your advantage instead! Invest in a solar roof ventilator that can help to keep your home comfortable in summer.

Solar Roof Ventilation vs. Whirlybird

For instance, you own a business, and you’ve got to choose between your two employees – one employee shows up to work regularly and produces consistent and reliable work results while the other employee will only show up now and then and provides variable work results. Of course, you’ll choose the first employee since he can offer the most benefit to your business.

Choosing between the wind-powered vent and the solar powered ventilation system is like the situation above – the wind vents will only be effective if the wind is available. Although occasional wind breezes are a joy to have especially when you’re spending some time outdoors, this is not going to do much when it comes to improving the humidity and hot air in your home.

On the other hand, the Solar Star roof ventilation works using a solar-powered fan capable of moving a large amount of air at any time when the sun is shining. In fact, it works even on partly cloudy days and during those days when there’s no wind at all. During the midday heat when there’s not much air moving, the solar-powered fan is still hard at work. The device also eases the burden of the air conditioning system, which means that the unit will not have to work as hard and this results in energy savings!

Why is Consistent Air Movement Important?

During the hottest months, the space in your attic could reach a temperature of up to 60-degree. And although hot air would rise, once it gets trapped in your roof, it will wind up heating the air at the lower floors. The trapped heat could lead to significant problems in your roofing and will cause extreme heat damage to your roof shingles and underlay. Also, if the weather will turn humid, the air inside your attic could get damp, providing for an ideal place for mildew and mold to grow.

By keeping the air to circulate in your attic and give it a place to escape, you’ll be able to maintain your roof’s integrity while improving the level of comfort inside your home. Furthermore, by taking away the damp and humid air and encouraging the movement of air, the ventilation system can significantly help to prevent damages in your home, most especially the growth of unhealthy mold.

How Good is the Solar Star Ventilation System?

The Solar Star is extremely good. As a matter of fact, comparison testing of the device and traditional wind vents using the Australian Standards during the calm sunny days has resulted in the removal of humid and hot air in a rate of 1080m3/hour – 1800m3/hour, which is about the same amount of 10 – 15 wind vents! This means that you may need to cover your entire roof with the vents to get the same effect.

If you want an economical way to keep your home healthier, drier, and cooler, the Solar Roof Ventilation system should be number on your list.

Comparison Between the Two

The whirlybirds have been around since forever. But lately, there have been some discussions regarding solar-powered roof ventilation system.

So what’s the hype over these solar fans?

At the moment, the focus is on the volume of the air that gets moved by the different roof ventilation fans available.

The average whirlybird moves at 100 cbm per hour, at a wind speed of 12 km/h. It’s difficult to find this kind of data from the manufacturers of wind-driven fans, although there seems to be a consensus when it comes to studying the different options for solar-powered roof ventilation that they’re equivalent to about 10 – 30 whirlybirds.

The only wind-driven fans that have capacities almost similar to the solar roof ventilation are the industrial whirlybirds. These devices are available in a wide variety of capacities and sizes. But then again, it’s hard to find the data that can support this.

The most well-known industrial whirlybird in Australia is the Edmonds branded at 900 mm with a capacity of 2700 cbm per hour at a wind speed of 12 km per hour. The biggest problem is that they mainly rely on wind. And as you know, it may not be too windy during the hot summer days when the ventilation is needed most.

Currently, it’s somewhat unusual to see industrial type whirlybirds being used at residential homes and offices, retirement villages, day care institutions, etc. You will only find these extremely large units in warehouses and factories.

However, if you prefer the roof ventilation that’s wind-driven to match the solar ventilation alternatives, you may need to check the extremely large industrial whirlybirds.

The biggest benefit of using whirlybirds is that they are cheaper to purchase. Yet, these devices would also incur installation costs. Those whirlybirds that are for residential use are quite easy to install, but if you’re not capable of doing it yourself, then you need to pay for the installation cost. The cost of installation could be several times the cost of the unit itself!

The Solar Roof ventilation system may be more expensive. However, they are up to 30 times more effective. To circulate enough air to improve the temperature in your roof space, the whirlybird will unlikely make any noticeable difference to both the roof space temperature as well as the amount of heat that radiates through the ceiling of your house.

If you consider the cost of buying 10 whirlybird units versus one solar powered roof ventilation system, the numbers will not stock up favorably for the whirlybirds, most especially if you need to hire a professional for the installation. Thus, the solar roof ventilation system is far more valuable if you need power and wanted to make a serious difference in the changes in the airflow in your house.

A shared role between greenhouse screens and roofs is the prevention of heat escape from the roof cavity which allows heat to accumulate and circulate inside your home. This can be quite helpful during the winter season however it can be the source of much discomfort among other problems during hot sunny days when temperatures within the home hit peak levels.

The sun, during warm seasons, can heat the roof to temperatures of up to 70 degrees which is quite extreme. This results in heat penetration through the ceiling and into the house causing great discomfort for anyone inside. It increases the chances of a person developing heat-related illness and exacerbates pre-existing chronic illness including diabetes. To counter this, ventilation and air conditioning longer which leads to increased energy and utility bills.

It is for this reason that highly efficient roof ventilators are needed. During the summer, roof ventilators come in handy as they manage the temperatures in the roof space area contributing to the comfort of members of the household. In the winter time, roof ventilators reduce moisture levels on the roof thereby protecting the roof from deteriorating too easily.

When speaking about roof ventilators, one of the more recognized brands is known as Whirlybird. One of the earliest air-driven roof vents, Whirlybirds have been present and used for several decades. Today we will explore whirlybirds to find out what they are and how they work.

Whirlybirds, also known as Whirligigs, belong to the roof ventilators family responsible for removing heat that is accumulated in the roof space via convection currents.

Whirligigs come in two forms namely passive wind-driven whirlybirds and active, powered whirlybirds. There are differences between these two whirlybirds are many; the chief difference is that the power-driven whirlybirds are electrically powered while wind-driven whirlybirds are run by wind and the continuously increasing in the roof space resulting from rising temperatures. Wind-driven whirlybirds are more popular and many people them as they are inexpensive.

In most cases, the exterior of whirlybirds is made up of aluminum or galvanized steel. The vent comprises of a flute-like head which is set on top of ball bearings, that enables the vent to spin. The outward appearance of a whirlybird resembles that of a turbine which is why you may find people calling it a turbine vent.

The Mechanics Behind How Whirlybirds Work?

Specially engineered fins are located at the metal top of the roof ventilators, and their work is to scoop the wind. This causes the wind to blow through the turbine making the vent rotate. The rotation of the vent creates a vacuum effect which allows the sucking out of the hot air from the roof

In other words, hot air, which normally finds its way to the roof space, is drawn upwards into the whirlybird and expelled to the outside through the vents.

Several whirlybirds working together will help alleviate built-up heat and humidity, in addition to enhancing the flow of air inside the house.

The whirlybird is designed in such a way that it resists rain. When in motion, the whirlybird’s circular force tosses away raindrops like vented air ensuring none of it gets in. Homeowners can rest assured that rainwater will not get in through the roof vent since whirlybirds are designed to be water resistant.

How Effective are Whirlybirds and What’s the Rate of Air Flow?

You can measure the effectiveness of whirlybird roof ventilators by their airflow capacity. That said, there are some factors that can affect airflow capacity such as the make and model of the whirlybird as well as the speed of wind in that locality. The performance of the whirlybird will differ depending on these factors. To illustrate this point, given winds of approximately 12Kph, in the space of one hour, a standard air-powered whirlybird can move around 8-150 cubic meters of air.

During times of strong winds, industrial whirlybirds can move anything between 2,500- 5,000 cubic meters of air per hour.

Satisfactory performance of whirlybirds requires winds of about 8Kph at the very least.

How Affordable Are Whirlybirds?

Whirlybirds are budget friendly with many of them going for less than $100. It is even possible to find some at the price of $60. This is one of the principal reasons why people choose whirlybirds over any other roof ventilation options. The flipside is that this affordability comes at a price. As Whirlybird manufacturers try to keep prices at an affordable range, they have also compromised certain features.

Listed below are some of the downsides you may experience when you purchase an air-driven whirlybird as your roof ventilation option:

1. Dependent on Wind Speed. The effectiveness of a whirlybird depends on the speed of wind in your area which essentially means that it will not operate if there is no wind (except the rotation that comes about following the expansion of air in the roof space when the sun heats the roof). This creates a problem in summer when the air is humid, and there is hardly any wind blowing or the speed doesn’t exceed 8Kph. In such instances, only the homes located in windy areas can profit from having a whirlybird- in any other area, wind-driven whirlybirds are not advisable. A natural solution would be to purchase a power-driven roof ventilator (mechanical whirlybird) however power-driven roof ventilators (whirlybirds) lost their appeal ages ago since installation will require the services of an electrician and they consume energy translating to higher energy bills.
2. Noise Pollution. The rotation of the turbines makes whirlybirds rather The turbines produce a low grinding or squeaking noise as they spin which they because they rub other parts of the ventilator in the process. When the turbine revolving at high speed or when the winds are really strong, the noise becomes louder. Further, as lubrication dries or when their bearings begin to come loose, whirlybirds may become noisy.
3. Low Efficiency. Compared to other roof vents, whirlybirds are not as efficient in moving air out of the roof space which is because the design of the whirlybirds is rather A solitary whirlybird does not have enough capacity to minimize humidity and temperature levels within a home. Studies indicate that the average-sided home requires 10-15 residential whirlybirds to cool it effectively. Picture installing 10 whirlybirds just to cool your home. If you were to purchase one whirlybird at $60, you would spend no less than $600, and this excludes installation fees; not forgetting the noise produced by all ten whirlybirds – it would be the kind of nuisance that gets on everybody’s nerves. At zero resistance, the average whirlybird can move approximately 100cbm while a powered or solar-powered roof ventilator will easily begin at a capacity of 1,000cmb per hour and go as high as 3,000cmb per hour.
4. Vulnerable to Malfunctioning. Whirlybirds are uniquely designed to resist rain however they may experience glitches in the event they catch foreign objects such as leaves or other debris. The spinning capacity of the whirlybird will decrease if a foreign object finds its way through the vents and into the turbines. Given the position of the whirlybird (on top of the roof) removing foreign objects is no mean feat. In the event, the turbine becomes damaged, the whole vent will require replacing.

Do Whirlybird Vents Leak?

Turbine vents are like exhaust vents. They have fins which open when the turbines turn in the wind. This turning (spinning) creates suction which draws up the hot and humid attic air to the outside. Turbines usually require little to no maintenance, but that does not mean that problems cannot occur. While turbine vents may leak, it doesn’t necessarily mean that the vent should be replaced.

• Rust or Obstructions

Under normal circumstances, even the slightest of breezes create a force that is strong enough to make the turbine vent spin. The spinning of the turbine causes air to be blown off from the vent, and this force is strong enough to blow away the rain from the openings in between the fins. Rainwater can infiltrate the openings if the vent is rusty since the turbine will be sticking and not moving as it should. Foreign objects near or inside the vent can prevent the turbine from spinning properly. It is important to inspect the vent and rid it of any obstructions. Additionally, replace rusty turbine vents.

• Loose Connections

High winds may cause the turbine vents to pull loose from their standpipes which may result in water penetration. Some turbine vents have their top portion mounted with a friction fit toward the lower standpipe portion. One other way in which water can penetrate is through poor anchoring of the flange that joins the pipe to the sheathing of the roof.  Examine your turbine vent to ensure that the top portion (which spins) is firmly attached to the standpipe by sheet metals screws. If the flashing comes loose against the roof, use roofing nails or rust-resistant screws to secure it. Exposed fastener heads should be sealed with roofing cement or silicone caulk.

• Unsealed Joints and Fasteners

At the time of installation, turbine vines will be sealed at various points to avert water penetration. These points include nail heads, the base of the vent, the bead that joins the upper section with the lower section, the point where the flashing and the stack meet as well as the stack’s vertical seams. These points can be sealed off using silicone caulk or roofing cement. Over the course of time, this sealing may deteriorate and require re-application.

• Improper Flashing

If you are experiencing leaks yet your turbine vent is not missing any fins and is in good working condition, then the problem could be at the bottom of the vent. Most vents have a base flashing incorporated that is usually made of metal sheets. These sheets are slipped under the shingles that lie above the vent while overlapping the shingles below. A bent or damaged flashing can let in wind-driven rainwater from below. Rejoin any raised segments of the flashing and seal off all edges and fasteners using roofing cement or caulk. A corroded flashing may possibly have holes in it that let in water and in this case, you should replace the entire vent.

DIY Installation

If you would like to go DIY and install a whirlybird on a metal roof on your own, you will save up on the installation cost. Purchasing the wind turbine is the sets you on the path to DIY-ing roof ventilation. In this section will cover how to install a wind turbine on a metal or corrugated iron roof.

You will require the following equipment:

• A ladder to help you access the roof; any other access to the roof can work too
• A drilling machine (battery powered or otherwise) and extension cable
• Marking Pen
• Angle grinder or tin snips that can cut through the thickness of your roof
• Socket to drive tek screws of 5mm (commonly 8mm hex)
• Additional flashing or ridge cap position fitment

Other materials that you will need are

• Tek screws that are 5mm in diameter x 20 long
• Sealing washers to suit

Before you embark on the installation process, it is important to decide on the precise position of the wind turbine(s). Ideally, you should aim to fit the bottom plate of the vent as far as possible under the ridge capping.

Step 1

Clearly, mark the spot chosen at the base of the ridge cap. Start by removing the fasteners that are holding the ridge cap in place on the spot you want to fit the bottom plates.

Step 2

Drive in the base plates under the ridge cap being careful to line it up. Mark the spot in which the hole will be cut.

Step 3

Remove the plate and gingerly cut the hole. You can choose to cut the hole using an angle grinder or the tin snips. The angle grinder will move quicker, but it is noisy and messy.

Step 4

If you want to use a trim ring, proceed now to fit it underneath the roof. If the trim ring cannot fit through the hole, you can either

• Use a string to lift the trim ring from inside the building or
• Choose a place to cut and feed the trim ring through that hole or lift or lift the trim ring through the using a string. Hold it in place and attach it from the outside (using your Tek screws plus sealing washers). Make sure you are doing this in the trough of the IBR and not the ridges. Use 4 screws for the job.

Step 5

Install the bottom plate on the rooftop and fasten it in place with Tek screws as well as sealing washers. This should be done on the ridges of your roof sheet and not the trough. Replace all the fasteners that hold your ridge cap in place. Pop rivets can do the job, but they should not be your first choice because they may cause leakage and they cannot bring together the sheets as they are set.

Step 6

Once you are done, carefully place your whirlybird onto the spigot of the bottom plate

Step 7

Now it is time to do some spinning. Spin the two halves of the neck at the same time to see how they relate to each other. Next, spin the whole neck and check how it relates to the base plate. Adjust the unit is if necessary to make sure the rotor (LID) stays horizontal. You can opt to make a slight jig to use a spirit level for leveling.

Step 8

If you are satisfied with what you have done so far, screw in the Tek screws through the openings at the base of the neck as well as the spigot.

Step 9

The holes in the four securing strips can be fastened using Tek screws.

Step 10

The DIY whirlybird installation is done. You may now get down from your roof and enjoy up to ten years hassle free operation

Solar Roofing as an Alternative to Roof Ventilation

Solar-powered roof ventilators are a worthy alternative to whirlybirds. Solar-powered ventilators also referred to as solar roof vents are roof ventilators that rely on solar energy. You can install a solar roof fan anywhere on your roof since exposure to the sun is almost constant in most parts of the roof.

You can install a solar roof fan wherever there is sunlight. Solar roofs perform optimally when the sun is shining directly at the top of the roof which is usually the time high-temperature levels are experienced. One more plus for solar roof ventilators is that they run at quiet whisper levels meaning there is no squeaky or grinding noise to be expected. Superior quality solar roof ventilation units such as Solar Whiz roof ventilators possess cutting-edge technology that allows to them operate on quiet whisper levels in full sun.

Compared to whirlybirds, solar roof ventilators are versatile and can be incorporate sleek designs that are less obtrusive and preferred by most people. To add to that, solar roof ventilators have a seamless external structure that prevents the foreign object from entering the roof.

The flipside to solar roof ventilators is that they are more expensive and often their price will be up to five times more than that of whirlybirds. But let’s face it – solar ventilators are a far more superior quality form of roof ventilation in comparison to the cheaper option that does not work as effectively.

The efficiency of solar roof ventilators is not to be underestimated. These ventilators have been shown to work up to 30 times better than the conventional whirlybird ventilators. As a matter of fact, the roof space temperature in a home can be controlled by a solitary solar-powered roof ventilator. In the long run, people find solar roof ventilators a more cost-effective option.

What’s the Best Roof Ventilator Option?

The affordability of the conventional whirlybird roof vents is the main reason why they are preferred by most customers who use the cost per unit approach. Unfortunately, this approach is faulty and does not consider the airflow capacity needed to efficiently and effectively ventilate the roof space. Whirlybirds have clearly been surpassed by several high-tech vents in this day, and they belong to an older generation of roof vents.

The efficiency level of a whirlybird is almost lacking when compared to modern roof vents, and their ability to perform is limited and tied to the drive from winds. Modern-day roof vents are either solar powered or mains powered. An interesting point to note here though is that the solar-powered fans found in the Australian market have a significantly higher airflow capacity compared to mains powered roof fans.

All in all, whirlybirds were good roof ventilators in eons past however technological advances in roof ventilation have overtaken this design have provided more efficient and cost-effective alternatives in the form of powered and solar-powered roof ventilators. As mentioned earlier, even a small home will require a minimum of ten whirlybirds to effectively ventilate roof space. A solar-powered ventilator is a more cost-effective option which is easy to install and does not require the services of an electrician and at the same time, has 10-30 times more capacity than a whirlybird. It also has 2-8 times more airflow capacity than popular powered roof vents.

Whirlybird or Ridge Vent?

Proper ventilation is crucial to the life of your roof. During winter months, attic ventilation is required to prevent the formation of ice dams while in summer, ventilation helps you prevent accumulation of hot air which may result in mold and it also protects the shingles against excessive heat.

Whirlybirds are normally installed on top of roofs, and they rely on wind power to suction hot and humid air from the attic. They comprise of a string of vanes that rotate as the wind passes through them.

Ridge vents, on the other hand, run across the peak of the roof. Ridge vents do not contain any moving parts and are like a screen. They permit heat to escape from the attic.

Installation Costs

Installation of a whirlybird is not so expensive because the process only requires removing a section of roof shingles and drilling an appropriately-sized hole to fit in the whirlybird. After which flashing, and sealant are applied around the opening to prevent water from seeping through.

Ridge vents are far more costly option since they run through the length of the roof. Installing the ridge vent system on an existing roof requires cutting away the entire peak. This is what drives up the cost.

Operational Benefits

Whirlybirds provide more airflow than ridge vents owing to their moving vents. However, in areas that do not experience much wind, turbines may not be the best roof ventilation option.

Ridge vents are passive systems that provide less air movement, and they can work well in moderate climates. Extreme climates will require one or more whirlybirds for proper circulation of air. For a ridge vent to perform optimally, it requires soffit venting which brings air up and pushes it out of the rooftop.

Whichever attic ventilation option you choose, it is vital to have it installed by a licensed and professional roofing contractor. The roofing contractor can also advise you on the best ventilation option for your attic.

Do Whirlybirds Work at Night?

If there is enough wind it will keep a whirlybird going, it will work all day, every day. The same situation will apply if air is continuously expanding in the roof space. There are other questions you should ask yourself – would you want your whirlybird to work all night during the cold season? On a hot and sticky summer evening when there is no breeze, the temperature of your roof will not change. Other roof ventilation systems offer you a night operation option, so it is it important to have this in mind when you make your purchase decision. A daytime effective roof ventilator is good but how good will it be at night when temperatures stand at 30 degrees? You want a ventilation system that works day and night.

Installation Cost of a Whirlybird

Time and cost of installing a whirlybird are generally like what you would spend installation any other type of roof ventilation. Whichever product you purchase, be it a whirlybird or solar ventilation or even a mains-powered extraction fan, you will have to spend money on installation. Installing a whirlybird in a two-story house is more expensive than having it done on a one-story house.

For you to notice a significant difference in roof space temperature, you will need to install 8-10 whirlybirds on the roof. The cost of installing all these units will need to be kept in mind not to mention how your roof is going to look like hosting 8-10 whirlybirds (aesthetics appeal may be lost here). If you choose to go for a higher capacity airflow alternative, i.e. solar ventilation or the powered roof vent, you will only to install one or two units, and that will decrease the installation costs quite significantly.

What Are Whirlybirds Made of?

Whirlybirds can be made of aluminum, stainless steel or galvanized steel. There are pros and cons attached to each material and depending on the shape and size of the whirlybird; the material used will affect its effectiveness, weight, durability, and ease of installation.

Where Should You Place the Whirlybird?

Placement of the whirlybird should be at the peak of the roof because this is the area it will pick up most of the rising heat also t-o receiving maximum wind power to facilitate its operations. It may be a struggle though, installing 8-10 whirlybird units at the uppermost points of your roof. It is likely you will run out of room for your units and must look for other places on the roof to install them, and this may adversely affect their effectiveness.

Air Capacity of a Roof Ventilator

This should be the most crucial consideration when choosing a roof ventilation system. Commercial whirlybirds have a capacity of 2,500 cubic meters hourly while non-commercial whirlybirds range between 100-200 cubic meters every hour. Before making the purchase, you should pity one product against another (i.e., a wind-driven system to a solar-powered system) this way you can compare their capabilities. Irrespective of whether you want a residential or commercial whirlybird, make sure that the product can create a noticeable difference in your roof space.

As you go through the information provided by roof ventilation manufacturers, it is easy to notice the considerable difference between the recommended ventilation capacities of whirlybirds and solar-powered systems. As you compare the air capacities of these two products, you will begin to realize that perhaps not even two or three whirlybirds will bring about a significant difference in roof space temperature for anything larger than a granny flat.

Efficient and effective roof ventilation may not be cheap, but it is worth remembering that you are not in the market for the price rather for value for your money. This means looking at the type of whirlybird or any other roof ventilation product that offers maximum airflow capacity for how much you want to spend. Quality value and not dollar value is the most critical part of your thought process as you choose a whirlybird roof ventilator. Do some research beforehand – you may find spending $100 in exchange for100 cubic meters of airflow per hour not worth the hassle.

How Many Units Will You Need?

The answer to this question will be based on the capacity of the roof ventilator you have chosen to purchase and its cost. You will need 8-10 residential whirlybirds before you notice any difference in the roof space temperature and this should be kept in mind as you look at installation costs unless you want to DIY. Commercial units vary depending on the building and its size.

Residential Roof Ventilation Comparison

Solar ventilation is a powerful alternative to unpowered ambient ventilation. There is a school of thought that claims that it is simply a reinvention of the wheel. Maybe so, but there are tyres that perform outstandingly compared to others!

Solar ventilators can extract huge amounts of air compared to the cheaper whirlybird options that you can find at the hardware store. Passive whirlybird ventilators solely rely on the winds to function while the solar ventilator only needs sunlight to start working. This enables solar ventilators to achieve more than your standard whirlybird.

• Solar Whiz

Solar Whiz offers a broad range of models starting from the small SW-RAF700 to the more powerful SW-RAF2100.  The RAF2100 is not the quietest model, but its sheer power makes up for it. Solar Whiz asserts that the air flow capacity measurement for their “Real-Air-Flow” product is based on actual capacity and not theoretical roof capacity which is quite the extraction potential. Adjustable thermostats and nighttime operations are included in the ventilators.

• Solar Star

These units are tidy-looking and come in two clearly distinct forms, i.e. RM1200 and RM1600. These ventilators can extract 1,200 to 1,600m3/h respectively and pride themselves on their noticeably superior power compared to the conventional whirlybirds.

• The Conventional Whirlybird

It is not easy to have an average estimate of either airflow capacity or sound because one whirlybird differs from the other. Our estimates are gathered from the cheap whirlybirds used by many homeowners. Whirlybirds can extract heat and moisture – the problem is that you will need to install anywhere from eight to ten for any temperature difference to be felt and this is in an average home!

• SolarArk

Solar Ark offers a range of roof ventilation models, and in this case, we will look at their SolarArk SAV20T model since it is one of their more efficient models for use in a home. Their conventional models are designed in such a way that both PV panels are built into the cap. Theoretically speaking, the SAV20T can extract 2718m3/h. It also has an inbuilt thermostat that gives you more control over the abilities of the ventilator.

• Edmonds Windmaster

The Edmonds’ Windmaster is the go-to roof ventilator for anyone in need of a cost-effective heat extraction solution. This whirlybird is perhaps the most reliable of them all. You can source information about this whirlybird openly because Edmonds has made it accessible to all. Unfortunately, once a whirlybird, always a whirlybird and the Windmaster cannot be relied upon to function effectively on its own. You will need to several Windmaster units to ventilate your property adequately. You can use the Windmaster as your measurement unit to inform the purchase decision for your roof ventilation needs.

• Edmonds Airomatic

This model makes the list of Edmonds’ most robust residential ventilators. This ventilator is not solar-powered instead it runs on mains electricity. Mechanical ventilators do not rely on wind or excessive heat to work; rather they run on electricity thereby providing dedicated ventilation that is capable of extracting heat and moisture. The Airomatic provides enough heat extraction, operates at relatively quiet levels and provides night cooling as well.

• Skydome Powervent

Among Skydome’s products, the SMV300 is one of the lesser known. Skydome is typically known for its skylighting solutions, but they also offer a somewhat powerful mechanical ventilator.  Skydome measures heat extraction in liters and they maintain that the SMV300 can expel 15,000 liters of air every minute. Now that sounds like a lot of air being extracted. When converted the 15,000 liters translates to approximately 900m3/h – so in normal language, the SMV300 can extract 900m3/h. This capacity is what has been theoretically stated but not practically proven.

• Solar Bright Maxbreeze

The Maxbreeze is somewhat interesting. There is no comprehensive guide on the extraction potential of the Maxbreeze however you will find a range of optional add-ons. The Maxbreeze’s extraction potential is somewhat arbitrary because it is measured by the angle of your roof and the size of your property.

What’s Best Way to Ventilate an Attic?

The RAVC recommends that the ventilation system in the attic always be balanced. This means equal amounts of

• Intake net free area via vents located in the soffit/overhang or by the roof’s lowest edge
• Exhaust net free is via vents mounted on or the roof’s peak.

This balance allows cool, dry air to come into the attic from the lowest point which in turn helps remove warm and moist air within the attic via the exhaust vents – down the entire base of the roof deck. RAVC member companies have wide-ranging offerings of both intake and exhaust vents.

If the ventilation system in the attic cannot be balanced, i.e. 50% intake and 50% exhaust, then you are better off having more intake than exhaust. It is rather unfortunate that many homes lack proper intake. Having more intake means that any excess intake will automatically become exhausted on the “windless” side of the house since the intake vents located on the windward side will have “pressurized” your attic. What happens next is that the intake vents located on the leeward side will “work hand-in-hand” with the exhaust vents to release air.

If your attic has more exhaust vents than intake vents, there is a likelihood of problems arising. This is because the exhaust vents may end up becoming intake vents to compensate for the imbalance. To illustrate this point using a ridge vent – it is likely that the ridge vent will pull air from the backside if it cannot get air from the intake vents. Similarly, a wind turbine will pull air from another wind turbine located close by on the roof if there is no enough intake to pull from on the roof.

Either way, the exhaust events are forced to ingest air and the weather which is not something they were designed to do.